there is a nexus mod here that changes the difficulty of survival:

http://www.nexusmods.com/fallout4/mods/333/?

and on the screen you can see that both the original 'very hard' and the original 'survival' have 0,5x for damage dealt and 2x for damage received

is that true? oO

is the only difference from very hard to survival the time that a stimpack needs to heal you?

I assumed survival would be something like 0,25x and 4x °_°

Iam using this Mod too. I never used any other Difficult Level except Survival but i changed his Mod for myself to 3x Player given Damage and 7x Player taken Damage. Its much more Fun because even one Pistol Shot can kill you. It was an Adventure to get out of Vault 111